This invention relates to skylight frameworks, and particularly to a framework of rafters and crossbars that insulates and cushions the framework with respect to the glazing panels that is supports and the structural frame upon which it is mounted.
Frameworks for the glazing panels that form a skylight are typically built up from extruded aluminum rafters and crossbars that are joined together in a variety of ways using threaded fasteners, clips, and the like. The glazing panels are typically pre-assembled in a factory with one or more glazing sheets in a panel and some supporting structure as part of the panel. This allows ease of installation directly to the framework. The framework may provide the necessary structural support for all of the weight and loads on the skylight. However, more typically the framework is itself mounted to a structural frame which may be built up from sections of steel for added strength and durability.
The aluminum framework is subjected to many temperature changes between the exterior and the environment that is enclosed by the skylight. The temperature changes can result in significant condensation of moisture on the surface of the aluminum elements. Heretofore, it has been typical to accommodate condensation by the use of gutters that are extruded into the outer surfaces of the aluminum elements to collect moisture and carry it away. An example of such gutters is shown in U.S. Pat. No. 5,092,087 issued Mar. 3, 1992, and assigned to the assignee of this application.